A differential is a device, usually employing gears, that is capable of transmitting torque and permitting rotation of different shafts at different speeds. Known differentials have cases that are cast from metals such as iron, and are often heavy and volumetrically undesirable. Assembly of known differentials can be difficult, oftentimes requiring bolting as well as welding. The use of “feed-in and rotate processes” when cast iron differential cases are manufactured is also known. Welding of the differentials formed from cast iron, in particular, can undesirably require the use of filler wire to provide an acceptable weld.
A particular differential case assembly is described in Assignee's co-pending U.S. Patent Application Publication No. 20110263374 to Cripsey, filed on Apr. 26, 2011, the entire disclosure of which is hereby incorporated herein by reference. The differential case assembly includes a differential case having an open end and a side wall with an interior surface, A plurality of major internal splines is formed on the interior surface of the side wall. The differential case assembly further includes a gear assembly. The gear assembly has a retainer insert and a cross pin. The retainer insert is disposed adjacent the interior surface of the side wall between a pair of the major internal splines. The retainer insert has a hole formed therein. The cross pin has an end mounted in the hole of the retainer insert. The cross pin aligns the gear assembly within the differential case.
There is a continuing need for a differential case assembly that is lighter compared to known cast iron designs, minimizes a required packaging space, minimizes assembly complexity, and can be employed with different numbers of gears. A differential case assembly that facilitates welding and eliminates a need for multiple nuts/bolts in the assembly process is also desired.